Temperature regulation



Oct. 3, 1933. A, J OTTO 1,928,737

TEMPERATURE REGULATION Filed Marbh so, 1932 s Sheets-Sheet 1 3maentor CiLQ/H IM/Z/ OM50 Gttomegs Oct. 3, 1933. A. J. OTTO TEMPERATURE REGULATION Filed March 30, 1932 3 Sheets-Sheet 2 0mm g. 013

(lttornegs Oct. 3, 1933. A. J. OTTO TEMPERATURE REGULATION Filed March 30, 1932 3 Sheets-Sheet 3 III I in

Patented Oct. 3, 1933 PATENT OFFICE TEMPERATURE REGULATION Arthur Otto, Milwaukee, Wis., assignmto Johnson Service Company, Milwaukee, Wis., a corporation of Wisconsin Application-March 30, 1932. Serial No. 602,037 19 Claims. (01. 2236-37) This invention relates to temperature regulation, and particularly to the regulation of temperature in rooms heated partly by a heater or heaters in the room itself (usually called direct 5 radiation) and partly by heated ventilating air which may be drawn from outside, or may be drawn partly from the outside (fresh air) and partly from within the heated building (recirculated air).

There are various systems of heating which respond to the above general description, but they fall into two broad classes, to each of which the present invention is applicable: (1) systems using a central air heating unit with a ventilating fan in conjunction with direct radiation in rooms, and (2) systems using a so-called unit heater or heaters mounted in each room in conjunction with direct radiation in such room.

A unit heater usually comprises fresh and recirculating air dampers, a circulating fan, and some heating means. Various methods of control are known, involving the control of one or more heating units, the control of mixing dampers, and like features, separately or in combination. The invention is not limited to any particular type of unit heater.

The invention is based on the discovery that while it is desirable that the maximum permissible proportion of heating be performed by heated ventilating air, the temperature at which such air is discharged in the room should be much 1ow-' er than is usual. The greater the temperature of the heated air discharged into the room, the greater the tendency of the air to stratify in the room. The tendency is toward high temperatures at the ceiling and low temperatures at the floor even where the temperature at the breathing line is correct.

The effect of introducing'the air at high temperature is particularly bad where the air enters near the ceiling or is directed toward the top of the room, as is usually the case. While the limit set, according to the present invention, is subject to some variation, I find it desirable to limit the temperature of the heated ventilating air to a maximum value approximately fifteen Fahrenheit degrees higher than the temperature sought to be maintained in the room. When this limit is not exceeded, the hot ventilating air' mixes readily with the air in the room, and serious stratification is not encountered.

In its broad aspects, the invention contemplates the control of heating primarily by controlling the temperature of air leaving the ventilating heater, the limitation of such heating by'imposing a maximum on such temperature, and the provision of supplemental heat by direct radiation in response to room temperature while the ventilating air is delivered at such maximum temperature.

Many unit heaters are equipped with thermostatic controls of their own, and perhaps the simplest embodiment of the inventive concept is to apply to such a unit heater a thermostat which will limit the temperature at which the ventilating air is discharged into the room, and use the unit heater in conjunction with direct radiation controlled by a room thermostat so adjusted that as the unit heater reaches its maximum heat output, and room temperature falls slightly, thedirect radiation will come into action and carry any excess load.

As a simple embodiment of the invention I show this idea applied to the unit heater described in the patent to Snediker, 1,813,261. In the Snediker patent, the thermostats are of the well known vapor pressure type.

As the preferred embodiment I show several rather better arrangements, in which a unit heater of the general type shown in the Snediker patent, and direct radiation, are controlled and their action coordinated by a pneumatic thermostat of the leak port type. By using a pneumatic leak port thermostat with a progressive relay, as the room thermostat, and a pneumatic leak port thermostat for the maximum limit thermostat and also for the minimum limit thermostat, if one be used, a very simple and practicable arrangement is secured. These two arrangements are selected as typical, first, of that characteristic embodii'nent of the invention in which separate thermostats are used, and, second, of that better embodiment of the invention where a single thermostatic system efiects all the controls.

Th invention is not, however, limited to the use of vapor pressure thermostats or pneumatic .thermostats, but may be worked out by the use and direct radiator connected for control single room thermostat.

Fig. 4 is a fragmentary view in front elevation showing the unit heater of Fig. 3.

Fig. 5 is a diagram of the control connections characteristic of Figs. 3 and 4. I

Fig. 6 is a modification simplified by the omission of the minimum control thermostat.

Fig. 7 is a diagrammatic view of an extremely simple system having a maximum but no minimum control thermostat.

Referring first to Figs. 1 and 2, the casing of a cabinet enclosing a unit heater is indicated at 10. This is provided with an air discharge grill 11, and two air inlet openings near the bottom. Of these the opening 12 is the recirculated air inlet leading from the room, and 13 is the fresh air inlet. The admission of air through these inlets is controlled by a damper 14 which is shifted by a motor 15 through speed reducing means 16, and an arm 17 under the control of a thermostat 18. The thermostat 18 is located in the recirculation opening 12 and is so arranged that when the air drawn in at the floor is below a definite temperature, say damper 14 will be shifted from the position of Fig. 2 to its right hand limit of motion (as viewed in this figure) This means that when the temperature of the air at the floor falls below a certain value, recirculation will take place. Under other conditions fresh air is drawn in. Circulation is induced by a motor 19 driving a fan 20, there being a fan at each end of the armature shaft. The motor is in constant operation.

In the upper part of the casing is the main heating element 21, the admission of heating fluid to which is controlled by a valve 22 actuated by a bellows motor 23. The pressure in the bellows motor 23 is communicated through pipe 24 from a thermostatic bulb 25. The bulb is mounted in a passage 26 through which some air is drawn from the room into the casing by the fan 20. The thermostatic bulb 25 is therefore responsive to room temperature.

Heating element 27 is located immediately beneath the heating element 21 and is supplied with heating fiuid under control of the valve 31 which is actuated by a bellows motor 28. This is connected by a pipe 29 with a thermostatic bulb 32 which lies between the two heating elements 21 and 2'7. The thermostat 32 functions to maintain the temperature of air flowing from the heater 27 to a value at or above a definite minimum. Thus the heating element 27 functions to assist the heating element 21 and when the heating element 21 is completely shutdown, as it may be in mild Weather, the heater 27 functions to temper entering air if it be below the desired minimum.

The structure so far described is that disclosed in the Snediker patent above identified.

To use such a heater in accordance with the present invention, a valve 33 is used which controls the fiow of heating fluid to both the valves 22 and 31, and this valve 33 is controlled by a bellows motor 34 connected by tube 35 with a thermostatic bulb 36. The thermostatic bulb 36 is placed at the point of discharge and is at a point in the flow path beyond both the heating elements. The thermostat 36 is set to limit to a definite maximum the temperature of air discharging through the grill 11.

In conjunction with a unit heater. equipped as just described, use is made of a. direct radiator 37 Whose heating action is controlled by a valve bya 38 actuated by a room thermostat 39. The thermostats are so adjusted that thermostatic bulb 32 exerts minimum temperature control and thermostat 36 a maximum temperature control on air discharging through the grill 11. Subject to these two limiting controls the thermostatic bulb 25 controls the action of the unit heater in response to room temperature.

In very mild weather the thermostatic bulb 25 functions to shut down the heater 21, and the thermostat 32 functions merely to preclude the admission of outside air below a desired minimum temperature. As the outside temperature decreases the heater 27 will be active and the heater 21 will be increasingly active, furnishing more and more heat as heating load increases. When the heating load reaches such a value that the maximum limit thermostat 36 takes control, the heating effect of the heaters 21 and 2'7 will be definitely limited. If the heating load increases the unit heater-will be then inadequate to carry the load, the room temperature will drop slightly, and the thermostat 39 will admit steam to the direct radiator 37 so that the direct radiation will carry the surplus load.

In a system of this character more than one unit heater may be used with one or more direct radiators, or a single unit heater may be used with one or more direct radiators.

In Figs. 3 and 4 a preferred embodiment of the invention is illustrated in which a single room thermostat controls both the unit heater and the direct radiator under the conditions existing when the air discharged from the unit heater is between the maximum and minimum limiting value, -and in which the limiting thermostats modify the control under other conditions.

In these figures the casing of the unit heater appears at 10, the air discharge at 11, the recirculating inlet at 12, and the fresh air inlet at 13. It will be understood that the recirculation damper 14 is controlled by the parts 15-18, as

before, and that there is a main heating unit 21 and a secondary heating unit 27, essentially similar to those already described. There is also a direct radiator 37 and steam valve 38*. ,The supply of steam or other heating fluid to the heater 21 is controlled by valve 22 and the supply of steam to the heating unit 27 is controlled by the valve 31. The steam to the direct radiator 37 is controlled by a valve 38 The valve 22 is controlled by bellows motor 23 The valve 31 is controlled by bellows motor 28 and the valve 38 by a bellows motor 39 The construction of this bellows motor can best be understood by a reference to Fig. 5. The bellows motors 23 and 28 are what are known as duplex motors. They are identical except for the strength of the spring used, and a description of one will suffice. They each comprise a base 41, a cap 42, and two metallic bellows diaphragms 43 and 44, one housed within the other and both connected to the base 41. Branch pipes 45 conduct pressure fluid to the space between the outer bellows 43 and the cap 42, while branch pipes 46 conduct pressure fluid to the space between the bellows diaphragms 43 and 44. Thus admission of pressure fiuid through either of the 3 two branch pipes 45 or 46 will result in forcing the valve stem 47 downward against the resistance of spring 48. This motion shifts the steam valve 51 toward its seat 52.

As stated the springs 48 are of different strengths in the motors 23 and 28, that in 23 being, for example, capable of resisting a pressure of eight pounds and that in 28 being capable of resisting a pressure of say eleven pounds. The bellows motor 39 has a single metallic bellows diaphragm 53. It is otherwise identical with the motors 23 or 28 and no further description is necessary except to point out that pressure acting in the bellows motor 39"- closes the valve 38" and that its spring will resist a pressure of four pounds.

The room thermostat is indicated generally at 55. This single thermostat performs the functions of the thermostats 25 and 39 of Figs. 1 and 2. The thermostat chosen for illustration is that described and claimed in the patent to Otto & Otto, No. 1,500,260, July 8, 1924, and so far as its operation is material to the present invention, it may be stated that air under pressure is supplied from a line 56 to a leak port 57 and diaphragm motor relay 58. A thermostatic bar 59 flexes with changes in temperature toward and from the leak port 57.

In Fig. 5 it is understood that the bar moves on rise of temperature to throttle the leak port. This variable throttling establishes a varying control pressure in the relay 58, and the relay 58 acts to establish a proportional or equal pressure on the branch line. 61

The thermostat is shown in section in Fig. 7, is familiar to those skilled in the art, and is fully described in the patent above identified, so that no detailed description is believed to be necessary.

The branch line 61 is connected directly to the space above the bellows diaphragm 53 of the motor 39 and is connected through a throttling needle valve 62 with the branch lines 45 which lead to the space above the bellows diaphragms 43 of the motors 23 and 28. Thus under normal conditions the thermostat 55 controls the three bellows motors 39 23 and. 28. Since the motor 39 has only a four pound spring it will act first. Consequently, on rise of temperature the direct radiation is shut off first. On further rise, the motor 23 having an eight pound spring, will function, shutting down gradually the heating unit 21. On still further rise, the motor 28*, with its eleven pound spring, will close, shutting down the heating unit 27.

In order to prevent the motor 28* from acting.

to close its valve 31 under conditions which would result in the delivery of air below the desired minimum, an insertion leak port thermostat 32 is used. This comprises a thermostatic element 63 which functions at the desired minimum temperature to force the valve element 64 away from a leak port 65 which is connected to the branches 45. Thus if the temperature immediately beyond the heating unit 2? falls below the desired minimum, the valve 64 will open and the leak port 65, which has a capacity slightly greater than the, setting of the needle valve 62, will vent the branches 45 sufllciently to cause motor 28 to open valve 31 more or less. The action will be graduated to maintain a constant exit temperature.

To limit the maximum temperature, a thermostat 36 of the insertion type, identical with the thermostat 32, is used. The thermostat 36 has an insertion thermostatic unit 66 (see Fig. 4) which operates a valve member 67 to control a leak port 68. The adjustment is such that the valve 67 will close the leak port 68 when the temperature of the air leaving the unit heater reaches.

the desired maximum. The 'leak port 68 is connected to the branches 46 which communicate with the space above the bellows 44 in the motors 23 and 28. Air is supplied through a branch of the main line 56 and restricting needle valve 69. The adjusted flow capacity of the needle valve 69 is less than the dischargecapacity of the leak port 68 so that until the maximum temperature 'is approached, the leak port 68 will assure venting of thepressure acting on the bellows 44. As the maximum is approached, the valve 67 throttles the port 68 and builds up a pressure on both bellows 44 which will gradually close first the valve 2.2 and thereafter, if necessary, also the valve 31 It will be observed that the thermostat 36 and the thermostat 32 are capable of taking control irrespective of the action of the thermostat 55.

On failure of pressure in the regulating systems all steam valves will open.

they are reversed relatively to their motors. The

motors 28 and 23 are of the single diaphragm type. The motor 39 is identical with the motor 39, but the valve 38 is reversely seated.

The thermostat 55 is identical with the thermostat 55 except that its thermostatic bar 59 is reversed, that is, it opens the leak port 57 on rise of temperature. The thermostat is fed through a supply line 56,"as before, and controls pressure in the branch line 61 which is connected directly tothe b'ellowsmotor 39 and is connected to the bellows motors 23 and 28 through a throttling needle valve 62, as before. A leak port thermostat 36 is connected to the motors 23 and 28 beyond the needle valve 62. The thermostat 63 is a maximum limit thermostat and is located similarly to the thermostat 36 in Fig. 3, but differs from the thermostat 36 in that it is reversed relatively thereto, that is, the leak port is opened on rise of temperature and opens at the desired maximum temperature. When it opens, it vents the motors 23 and 28 at rates attimes greater than the rate of supply through the needle valve 62. Consequently,'when the maximum limit is approached, the thermostat 36 takes control of the motors 23 and 28 but does not afiect the motor 39'. The motor 39 is provided with an eleven pound spring, the motor 23 with an eight pound spring, and the motor 28 with a four pound spring, the order of spring strength being the reverse of that described with reference to Figs. 5 and 6, because of the reversed arrangement of the thermostats and valves.

In Fig. '7, as the temperature rises, the thermostatic bar 59 moves away from the leak port 57 and reduces the pressure on the line 61. Such reduction causes the valve 38 to close first, shutting down the direct radiation. If the leak port maintains the heating valves open by maintaining pressure on the line 61. If under these con-' ditions the maximum discharge temperature from the unit heater is reached, the thermostat 36 starts to vent and eifects regulation by assuming control of the motors 23 and 28 In all of the systems above described, there is a primary control of direct radiation and of the unit heater in response to room temperature, and the control is so graduated that the unit heater continues in operation after the direct radiation has been shut down.

In. the structures of Figs. 1 to 5 inclusive, the maximum and minimum temperatures of dischage from the unit heater are controlled by limiting thermostats which assume control when those limits are reached, irrespective of the action of the room thermostats.

In Figs. 6 and '7 the minimum control is absent but the maximum control is present.

Two characteristically different thermostatic systems have been illustrated, the purpose being to suggest the possibility of using various difierent types of thermostats, rather than to suggest any limitation to the specific forms illustrated.

The duplex valve motors are illustrated as.

typical of any mechanism which will respond independently to either of two motive pressures to shut down the flow of heat. This is simpler and more compact arrangement than that which would be secured by the use of two motor actuated steam valves connected in series in the same steam line. Such an arrangement is shown, for example, in Fig. 1, where the valve 33 is in series with each of the valves 22 and 31. This series valve arrangement could, however, be used in lieu of the duplex valve motors of Figs. 5 and 6, the substitution being obvious.

/ What is claimed is:

1. The method of maintaining a substantially uniform elevated temperature in a space, which consists in delivering heated air to such space; varying the delivery temperature thereof up to a chosen maximum to vary the rate of heat delivery in response to temperature in the heated space; and delivering additional heat by direct radiation to the space in response to the temperature therein when such air delivery temperature attains said maximum.

2. The method of maintaining a substantially uniform temperature in a space, which consists in delivering air at an approximately uniform rate to said space; heating said air variably in response to variations in temperature in the space; limiting the maximum temperature of such heated air; and supplying heat directly to the space in response to temperature depressions occasioned by such limitation.

3. The method of maintaining a substantially uniform temperature in a space, which consists in delivering heat to the space indirectly at a variable rate by the delivery of air at a substantially uniform flow rate and at variable temperature, and directly at a variable rate by radiation, regulating the delivery of heat in response to temperature in the enclosure and limiting the maximum temperature of the delivered air.

4. The method of maintaining a substantially uniform temperature in a space, which consists in delivering heat to the space indirectly at a variable rate by the delivery of air at a substantially uniform flow rate and at variable temperature, and directly at a variable rate by radiation, regulating the delivery of heat in response to temperature in the enclosure and limiting the maximum and minimum temperature of the delivered air.

5. The method of maintaining a substantially uniform temperature in a space, which consists in delivering heat to the space indirectly at a variable rate by the delivery of air at a substantially uniform rate and at variable temperature; controlling the temperature of' the delivered air in response to the temperature in the space; limiting the temperature of the delivered air to a definite maximum and while such temperature is maximum supplying additional heat to the space by direct radiation, and controlling the last mentioned 'supply in response to temperature in the space.

6. The method of maintaining a substantially uniform temperature in a space, which consists in delivering heat to the space indirectly at a variable rate by the delivery of air at a substantially uniform rate and at variable temperature; controlling the temperature of the, delivered air in response to the temperature in the space; limiting the temperature of the delivered air between a definite maximum and minimum and while such temperature is maximum'supplying additional heat to the space by direct radiation, and controlling the last mentioned supply in response to temperature in the space.

'7. An automatically regulated heating system, comprising in combination a primary heating means; means for passing air in heat exchanging relation therewith and delivering it to the space to be heated; a secondary heating means arranged to deliver heat directly to said space; thermostatic means subject to the temperature in said space and controlling said secondary heating means; thermostatic means for varying the heating eifect of said primary means in accord ance with the demands for heat; and thermostatic means subject to the temperature of air heated by said primary means and serving to limit said temperature to a chosen maximum.

8. An automatically regulated heating system, comprising in combination a primary heating means; means for passing air in heat exchanging relation therewith and delivering it to the space to be heated; a secondary heating means arranged to deliver heat directly to said space; thermostatic means subject to the temperature in said space and controlling said secondary heating means; thermostatic means for varying the heating effect of said primary'means in accordance with the demands for heat; and thermostatic means subject to the temperature of air heated by said primary means and serving to limit said temperature between a chosen maximum and minimum.

9. An automatically regulated heating system, comprising in combination a primary heating means; means for passing air in heat exchanging relation therewith and delivering it to the space to be heated; a secondary heating means arranged to deliver heat directly to said space; thermostatic means subject to the temperature in said space and normally controlling both said heating means; and thermostatic means subject to the temperature of air heated by said primary means and arranged to exercise a secondary control on said primary means to limit the temperature of said air to a chosen maximum.

10. An automatically regulated heating system, comprising in combination a' primary heating means; means for passing air in heat exchanging relation therewith and delivering it to the space to be heated; a secondary heating means arranged to deliver heat directly to said space; thermostatic means subject to the temperature in said space and normally controlling both said heating means; and thermostatic means, subject to the temperature of air passed in heat exchanging relation with said primary means, and arranged to exercise a secondary control on said primary means to maintain the temperature of said air between chosen maximum and minimum limits.

11. An automatically regulated heating system, comprising in combination a primary heat ing means; means for passing air in heat exchanging relation therewith and delivering it to the space to be heated; a secondary heating means arranged to deliver heat directly to said space; two separate thermostatic means both subject to the temperature in said space, and each controlling a corresponding one of said heating means; and thermostatic means subject to the temperature of air heated by said primary heating means, and

arranged to exercise a secondary control on said primary heating means to limit the temperature of said air to a chosen maximum.

12. An automatically regulated heating system, comprising in combination a primary heating means; means for passing air in heat exchanging relation therewith and delivering it to the space to be heated; a secondary heating means arranged to deliver heat directly to said space; two separate thermostatic means both subject to the temperature in said space, and each controlling a corresponding one of said heating means; and thermostatic means subject to the temperature of air passed in heat exchanging relation with said primary means, and arranged to exercise a secondary control on said primary means to maintain the temperature of said air between chosen maximum and minimum limits.

13. The combination of a controllable primary heating means adapted to heat air to a variable temperature and deliver it to a space to'be heated; a controllable secondary heating means arranged to deliver heat directly to said space; and thermostatic means responsive to temperature in said space and also to the temperature of said heated air; said thermostatic means controlling both said heating means and serving, on increasing demand. for heat to increase the output of said primary means until the temperature of the delivered air approximates a chosen maximum, and at higher demands for heat bringing said secondary means into action without increasing the output of the primary means.

14. The combination of a unit heater arranged to deliver heated air to a space to be heated; a direct heater in said space; thermostatic means for varying the output of said unit heater by varying the temperature of the delivered air; thermostatic means for limiting the maximum temperature of the delivered air; and thermostatic means responsive to room tempera ture for controlling said direct heater.

1 5. The combination of/a unit heater adapted to deliver air to a space to be heated, at a substantially uniform rate and at variable temperature; a direct heating means adapted to deliver heat to said space at a variable rate; thermostatic means subject to the temperature in said space and arranged to control said heating means; and thermostatic means subject to the temperature of the delivered air and operative at a chosen delivery temperature to prevent the first named thermostatic means from further increasing the temperature of the delivered air.

16. The combination of means for supplying air to a space to be heated; means for supplying heat to said air; pressure motor actuated means serving to control the rate of supply of said heat; means for supplying heat directly to said space; pressure motor actuated means serving to control the supply of heat by the second named heating means; a pressure line connected to said motors; a thermostat responsive to temperature in said space and controlling pressure in said line; a constriction in said line between said thermostat-and one of said motors; a leak valve for modifying pressure in the motor just mentioned; and a thermostat subject to the temperature of said heated air and controlling said leak valve.

17. Thecombination of means for supplying air to a space to be heated; means for supplying heat to said air; pressure motor actuated means serving to control the rate of supply of said heat; means for supplying heat directly to said space; pressure motor actuated means serving to control the supply of heat by the second named heating means; a pressure line connected to said motors; a thermostat responsive to temperature in said space and controlling pressure in said line; a constriction in said line between said thermostat and one of said motors; a leak valve for modifying pressure in the motor just mentioned; a thermostat subject to the temperature of said heated air and controlling said leak valve; and means for causing said motors to respond to dif ferent pressures.

18. The combination of means for .supplying air to a space to be heated; a plurality of heaters for supplying heat to said air; pressure motor actuated means arranged to put said heaters successively into and out of action as the actuating pressure varies; a heater for supplying heat to said space directly; pressure motor actuated means serving to control the supply of heat by the second named heater; a pressure line connected to said motors; a thermostat responsive to temperature in said space and controlling the pressure in said line; a constriction in said line between said thermostat and the first named motor; a leak valve for varying the pressure in the first named motor; and a thermostat subject to the temperature of said heated air and controlling said leak valve.

19. The combination of means for supplying air to a space to be heated; a plurality of heaters for supplying heat to said air; pressure motor actuated means arranged to put said heaters suc cessively into and out of action as the actuating pressure varies; a heater for supplying heat to said space directly; pressure motor actuated means serving to control the supply of heat by the second named heater; a pressure line connected to said motors; a thermostat responsive to temperature in said'space and controlling the pressure in said line; a constriction in said line between said thermostat and the first named motor; a leak valve for varying the pressure in the first named motor; a thermostat subject to the temperature of said heated air and controlling said leak valve; and means for differentially biasing said motor means to shut down the second named heater in advance of the first named.

ARTHUR J. OTTO. 

